ℹ️ This is a quick blog post to mainly play with Jekyll.
Not long ago Windows on my laptop reported that Skype was last used on 1/1/1601.. While I rarely use Skype now-a-days, it surely wasn’t that long! January 1st does hint at some kind of a date baseline, just like the Unix epoch, but why 1601?
Of course, this was a quick answer to look up and it turns out to be that “1601 was the first year of the 400-year Gregorian calendar cycle at the time Windows NT was made”1. More specifically, “The FILETIME structure records time in the form of 100-nanosecond intervals since January 1, 1601”2.
While on the subject, it’s worth recalling that Unix time records 1-second intervals since January 1, 1970.
Actually, there seem to be a lot more such Epoch dates, not just the ubiquitous Unix and Windows ones.